Psychrometrics, Humidity & IAQ

This is the second article in a three-part series where we explore advanced psychrometrics. The source material for each of the articles in this series is ACCA Manual P Sections 3, 4, and 5. This article is based on information found in Section 4. If you followed the previous advanced psychrometrics article, you now know […]

This is the first of a three-part series of articles that will dive deep into advanced psychrometrics. The source material for each of these articles may be found in ACCA Manual P Sections 3, 4, and 5. This article is based on information found in Section 3.  Psychrometrics is the study of the physical and […]

At the time of the publication of this article, COVID-19 (coronavirus) is spreading across the world at an alarming rate, and many people have self-quarantined to help slow or stop the spread of the virus. These precautionary measures are prudent and responsible. However, with the increased amount of time people spend inside their homes, there […]

Oxidation is the loss of electrons, reduction is the gain of electrons, and the reaction is what occurs between the two. When we talk about chemistry or chemical reactions, we are really talking about an electrical interaction between molecules seeking equilibrium. In other the words, the old “high voltage goes to low voltage” rule applies […]

The Four Ps of IAQ I’m not the first, second, or probably even the thirty-second person to write about improving indoor air quality problems using the four Ps approach. It’s a well-known thought process in the building science community—not sure if that’s the case in HVAC circles. The first P is for pollutants. In this […]

Every piece of air conditioning equipment can move a certain amount of heat BTUs (British Thermal Units) at set conditions. In most cases, during the cooling mode, a portion of those BTUs will go toward changing the temperature of the air, and a part will go toward changing vapor water in the air into water […]

This article is written by tech and business owner Genry Garcia from South Florida. I met Genry at a Solderweld demonstration, and he later offered to write this excellent article. Thanks, Genry! Though dehumidifiers have increased in popularity, thanks in part to the implementation of new building codes, they have become a kind of red-haired […]

Does heating the air cause the humidity in the air to decrease? Yes and no. Heating air causes the RELATIVE humidity percentage to decrease, but it does not change the overall moisture content in grains of moisture per lb of air. Many old-timers will swear a blue blaze that oversizing a furnace will directly result […]

I was listening to someone talk about air relative humidity the other day while looking at a psychrometric chart, and he commented that the chart ends down at freezing (32°F) because “all the water freezes out of the air at that point.” I think I made this Jed Clampett face: The psychrometric chart is designed […]